Giant pneumatic tire



Dec. 2, 1952 A GlEBHART 2,620,009

GIANT PNEUMATIC TIRE Filed Feb. 23, 195o Patented Dec. 2, 1952 GIANT PN EUMATIC TIRE Anton Giebhart, Baden,v near Vienna., Austria,

assigner to Semperit Osterreichisch-Amerikanische Vienna, Austria Gummiwerke Aktiengesellschaft,

Application February 23, 1950, Serial No. 145,732

r In Austria March 18, 194.9

The invention relates to pneumatic tires having in the inflated condition an outer diameter of at least 35%", a width of at least 'l1/2 and an anti-skid tread of a surface width of at least 51/2. Such tires, which will be referred to as giant pneumatic tires, are used on heavy motor vehicles such as buses, coaches, lorries, or trucks designed for running at high speed on metalled roads, as distinguished from tractors or the like designed for ploughed fields or other soft ground and for comparatively much lower speeds than the aforesaid road vehicles.

It is the principal object of the invention to provide a giant pneumatic tire having a life period or milage exceeding the maximum hitherto thought to be attainable by about one half.

It is another object of the invention to provide a giant pneumatic tire having an anti-skid tread of an average life period or milage equal to that of the canvas cover so as to avoid retreading of the latter.

It is also an object of the present invention to provide a giant pneumatic tire having an antiskid tread of a height substantially exceeding what has been hitherto considered to be the maximum height of about 8% of the surface width of the tread or about 1.2% of the tire diameter in the inflated condition in view of internal heating caused by the work of kneading It is still another object of the invention to provide a giant pneumatic tire having an antiskid tread wherein bulky accumulations of undivided rubber masses is avoided in order to prevent excessive heating.

It is yet another object of the invention to provide giant pneumatic tire having an anti-skid tread which is dissolved into elements of a pattern affording thorough ventilation to all the said elements in order to prevent excessive heating.

It is yet another object of the invention to provide a giant pneumatic tire capable of being moulded in a bi-partite mould, i. e. not requiring a trl-partite mould for its manufacture.

Other objects will appear from the description of a typical embodiment of the invention which will be given later in this specification by way of example.

According to a main feature of the invention a giant pneumatic tire as defined hereinabove comprises an Vanti-skid rubber tread having a cambered surface of a curvature parallel to that of the canvas cover of the tire, to which it is vulcanized the said tread consisting of a continuous 'base layer and of an anti-skid pattern projecting therefrom a height of 11-20% of the surface 2 Claims. (Cl. 152-209) width of the said tread and having an aggregate surface area not exceeding of the overall surface area of the said tread.

Preferably the said antiskid pattern comprises a continuous central band and at least two rows of pattern blocks arranged on each side of the said band, separated therefrom and from one another by continuous circumferential recesses, the pitch of the rows of said pattern blocks adjacent the said central band amounting to .51.% of the circumference, and the pitch of the rows of pattern blocks adjacent the edges of the tread amounting to 1-2% of the circumference. Y

Preferably the said continuous central band is made Zig-zag shaped and has the subsidiary but not inherent feature of transverse recesses arranged Vat alternate reentrant corners on both sides. Such a central band contributes to the anti-skid properties of the tread while avoiding excessive accumulations of undivided rubber, and is capable of being moulded in a bi-partite mould as distinguished from a zig-zag band dissolved into transverse laminations or blocks which would require a tri-partite mould i. e. a mould divided at the edges of the anti-skid tread, in order to be capable of freeing from the mould the segments of the matrix, which extend over the whole tread surface.

The said central band is separated from the adjacent row of pattern blocks by continuous circumferential recesses and divide the individual rows of pattern blocks from one another.

In the case of a zig-zag central band, the pattern blocks of the adjacent rows have preferably roof-shaped corners jutting out towards the reentrant corners of the zig-zag band so as to dene a zig-zag shaped circumferential recess between themselves and the said central band.

The said pattern blocks of the inner rows may have roof shaped corners jutting out towards the adjacent outer rows as well.

Preferably the pitch of the outer rows is twice that of the inner rows, and the blocks of the said outer rows have roof-shaped corners jutting out towards every alternate reentrant corner between twc blocks of the inner rows.

Preferably the transverse recesses separating the individual pattern blocks of each row from one another are narrower in the inner rows and wider in the outer rows, where they may flare out towards the edges of the tread. Thereby an excellent ventilation of the tread is achieved, and overheating is avoided.

With these general statements of the objects and purposes of my invention I will now proceed to describe an embodiment thereof and the manner in which my invention is carried out, and it will be understood that while I have described what may be considered as a preferable embodiment of my invention, I do not limit myself to the precise conditions or 1; ro1oortionsv herein set forth,. as they 'may bei varied by Ithose y. 'skilled-.in the art in accordance with the particular purposes for which they are intended and the conditions under which they are utilised,

In the accompanying drawing:

Fig. 1 shows a giant pneumatic tirein cross section along the line I-rof" Fig; 2,

Fig. 2 shows part of the: tirenplanview; and

Fig. 3 shows a sector` of the tire in side elevation.

The canvas cover I of 4.thectireisslcuiltupizof rubber impregnated cord fa'br-c and`has. beads`f2 on the edges and an anti-skid rubber tread3 on top. The tread surface has a width b of atleast .5l/2". The diameter d of the tire amounts in the i'inated condition t-ozat `leastI 35 1/ ,and the Vwidth "B'thereof to at vleast'f'l 1/2".

The tread surface iscan'rbered andhasav curvaituresubstantiallyy parallel to the'middlelayer I jof'thecanvas cover I lin order to-*prevent'any thickening of the Arubber at the edgesof the-tread *surface Theanti-skid pattern provid-edy in Ythetread consistsofia continuous vcircumferential 'zigezagl *'band" 5 having transverse recesses- I 6 atv alternate yreentrant `corners Yon" `b othv sides. An innerrow 6 'and anouterrow'l of pattern blocks is'arranged on each side ofthe Said Ycentral hand-5. #Acon- "tinuous circumferential-recessi-S separates thel '-'Eachouter'row I isdivided int-o individual-'pat- A,

vternhlocks I4 `Icy comparatively Awide transverse :.--recesses I4 which -are `outwards and issue on the Asi-desof the' tread' into the-open air 'lwhereby a ,good ventilation of the tread-fromfthefcentral hand -outward is Asecured by-af-systemfcf fin-tercommunicating rcircuni-f-er-ential and transverse channels.

Y Whlethe' usual thickness^a^ 'ofth-. base layer lis maintained, l the height ofE the 1anti=skid V"pattern amounts `to'at least 111% lofthelwdthbfo the treadsurface, and-may vary4r `between '11i-and v'520% "according to the Vsize of they tires-whichfcor- "responds to' at -least`2-4'% ofthe-.iouterfdia-met-er d ofthe tire. l

`The totalareaof the recessesl; IlIl, I 2;.1and I4 amounts to at least 25% of the overallr treadfsurface area, i. e.t-he aggregateeareafoffthe vcentral *ba-nd 5"and-'of i' the pattern f-blccks vISsarid I5 Mamounts to -less t'ha: 1"1"75"704 of thefsai-'d' over-alli' area.

"The pi-t'chpf the antieskid vpattern is 'com-paraff tively small in' relation 1 to "thef cimum-ferenceV of the tire; itarnounts tofsll'%'1of1thecircumfer fenceforthe .inner vrow-l.'lpofipatternhlocks I3 and tto. 142%'. forthel outerrows 17 zofi. pattern blocks' :I 5. `Oneil pattern1 kilo ck'- I5 is thus associatedfwa'th two pattern blocks I3.

As will beseenin Fig.-2, the--inner andouter :sidefaces .of the ,pattern blocks .I,3.,.are.roof shaped, and so are thefinneizsi'de.Iacesaofth-e pattern blocks I5. The corners at 'the' inner side faces of the pattern blocks I3 jut out towards the reentrant corners of the central zig-zag band 5 whereby the circumferential recess 9 is also given a zig-zag shape. The corners of the pattern 5 blocks I5 jut out towards alternate reentran-t ...corners formed .between adjacent .blocks I3 of the ".-inner rows tatthe outerside faces thereof, while the other alternate reentran't Icorners of the inner row 6 are in juxtaposition with the aring 10 transverse recesses I4 between the pattern zbldcks I5.

...Therebyfthe tread is dissolved into a most com- 1pacIr-.pz'ittern VfV anti-skid excrescences 5, I3, I5 enclosing `a-fmaximum area of recesses 9, I0, I2,

`42between.onecanother, whereby an excellent anti-'skid elect combined with very good venti- VLlationfsof the itread is achieved.

-^What I claim is: v1...In Aor for a giant pneumatic tire having in the infiated condition an outer diameter of at least 3-51/2". and a width of at least 7%". anantiskid rubbertread' offai surface'width of at least 5 1/2 comprising .a' continuous .baselayen` a "con- .tinuous :central Zig-zag shaped band having transverse. recesses atalternate reentrant corners, an inner rowof pattern blocks arrangedlonea'ch Yside of thesaidcentral bandfseparatedlthere- Tfr-om ',.by continuous .circumferential recesses, the., pattern .blocksl of .the .,saidlinnerrowslhaving being. separated from -onea-notherlby .comparatively narrow `transverse`recesses,. an outer row Aof .pattern blocks. arrangedonach. edge of'the said tread, .-separated from '.the radjacentinner .row of,..pattern blocks'byn acontinuouscircurnfersential recess, .the pattern; blocks cof. said outer .Y rows-having.,appitch :of 1i .to .2 %...flthe circum- .ference and.. being. separatedv `fromaone= ,another by comparativelywide transverse recesses,fflarng #40 outward, .thesaid centralbandandfinner and i and .thefpattern blocksaoftthe. ou-ten rowsshaving Y f rooff-shapedfcorners jutti-ng. outtoward` alternate reentrant Y. corners i `between ,blocks Aof i vsaid inner rows, said transverse recesses between ,pattern blocks,ofr-thefouter rows bei-ng ain alignmentwvith transverse recessesbetweenthe patterneblocks. of @theI inner. rows. Y

TANTO-N GIEBHART.

:REFERENCES orceED Y sfheofoliowing referencesarefrofrecord in the IemthiS patent:

{UNITEDsTATEs'PATENrs Austria @Apr-16,1940 

